Hot-melt adhesive composition, precoated surface material for automobile interior, automobile interior material, and method of producing bonded body

Abstract

Provided is a hot-melt adhesive composition, comprising: an α-olefin (co)polymer (A) that is produced using a single-site catalyst and has a Shore A hardness of 80 or more; an α-olefin (co)polymer (B) that is produced using a single-site catalyst and has a Shore A hardness of less than 80; an ethylene-polar group-containing monomer copolymer (C); and a polypropylene-based wax (D), wherein the polypropylene-based wax (D) is comprised in an amount of 60 parts by mass to 300 parts by mass with respect to a total of 100 parts by mass of the α-olefin (co)polymer (A), the α-olefin (co)polymer (B), and the ethylene-polar group-containing monomer copolymer (C).

1 . A hot-melt adhesive composition, comprising:
 an α-olefin (co)polymer (A) that is produced using a single-site catalyst and has a Shore A hardness of 80 or more;   an α-olefin (co)polymer (B) that is produced using a single-site catalyst and has a Shore A hardness of less than 80;   an ethylene-polar group-containing monomer copolymer (C); and   a polypropylene-based wax (D),   wherein the polypropylene-based wax (D) is comprised in an amount of 60 parts by mass to 300 parts by mass with respect to a total of 100 parts by mass of the α-olefin (co)polymer (A), the α-olefin (co)polymer (B), and the ethylene-polar group-containing monomer copolymer (C).   
     
     
         2 . The hot-melt adhesive composition according to  claim 1 , wherein the α-olefin (co)polymer (A) comprises at least one selected from the group consisting of polypropylenes, ethylene-propylene copolymers, and propylene-butene copolymers. 
     
     
         3 . The hot-melt adhesive composition according to  claim 1 , wherein the α-olefin (co)polymer (B) comprises a repeating unit derived from propylene as a part of a copolymerized component. 
     
     
         4 . The hot-melt adhesive composition according to  claim 1 , wherein the ethylene-polar group-containing monomer copolymer (C) comprises at least one selected from the group consisting of ethylene-vinyl acetate copolymers and ethylene-ethyl acrylate copolymers. 
     
     
         5 . The hot-melt adhesive composition according to  claim 1 , wherein the polypropylene-based wax (D) has a softening point of 90° C. or higher. 
     
     
         6 . The hot-melt adhesive composition according to  claim 1 , comprising a tackifier (E). 
     
     
         7 . The hot-melt adhesive composition according to  claim 6 , wherein the tackifier (E) comprises at least one selected from the group consisting of hydrogenated petroleum resins, terpene resins, and hydrogenated terpene phenol resins. 
     
     
         8 . The hot-melt adhesive composition according to  claim 1 , comprising an antioxidant (F). 
     
     
         9 . The hot-melt adhesive composition according to  claim 1 , having a melt viscosity of 10,000 mPa·s to 50,000 mPa·s at 180° C. 
     
     
         10 . The hot-melt adhesive composition according to  claim 1 , which is for an automobile interior material. 
     
     
         11 . A precoated surface material for automobile interior, comprising:
 a surface material for automobile interior; and   a hot-melt adhesive layer formed from the hot-melt adhesive composition according to any one of  claim 1  on the back surface of the surface material for automobile interior.   
     
     
         12 . An automobile interior material, comprising:
 a molded article for automobile interior; and   the precoated surface material for automobile interior according to claim  11 , which is bonded to the molded article for automobile interior via the hot-melt adhesive layer.   
     
     
         13 . A method of producing a bonded body,
 wherein   the bonded body comprises: a first substrate; and a second substrate bonded to the first substrate via a hot-melt adhesive layer formed from the hot-melt adhesive composition according to any one of  claim 1 , and   the method comprises a step of bringing a mold and the hot-melt adhesive composition into contact.   
     
     
         14 . A method of producing a hot-melt adhesive composition, the method comprising:
 preparing an α-olefin (co)polymer (A) that is produced using a single-site catalyst and has a Shore A hardness of 80 or more, an α-olefin (co)polymer (B) that is produced using a single-site catalyst and has a Shore A hardness of less than 80, an ethylene-polar group-containing monomer copolymer (C), and a polypropylene-based wax (D); and   melt-mixing the polypropylene-based wax (D) in an amount of 60 parts by mass to 300 parts by mass with respect to a total of 100 parts by mass of the α-olefin (co)polymer (A), the α-olefin (co)polymer (B), and the ethylene-polar group-containing monomer copolymer (C).